Selective scale drawing instrument



March 18, 1958 w. MAJOR 2,826,816

SELECTIVE SCALE DRAWING INSTRUMENT 2 Sheets-Sheet 1 Filed July 25, 1955William 8. Major IN VEN TOR.

2 Sheets-Sheet 2 W. B. MAJOR SELECTIVE SCALE DRAWING INSTRUMENT March18, 1958 Filed July 25, 1955 William B. Major INVENTOR.

United States Patent 2,826,816 SELECTIVE SCALE DRAWING INSTRUMENTWilliam B. Major, Burbank, Calif. Application July 25, 1955, Serial No.523,996 3 Claims. (Cl. 33-107) This invention relates to improvements inmultiscale instruments especially useful in various types of draftingwork.

An object of this inventon is to provide a multiscale instrument whichis compact, thin and very easily used in drafting work.

A more specific object of the invention is to provide a multiscaleinstrument which includes a housing having I entrances along the sideedges thereof, this housing being arcuate in cross-section andcontaining two or more blades,

each blade having scale indicia thereon and means opergreat number ofindicia crowded in a small space is' avoided.

These together with other objects and advantages which will becomesubsequently apperent reside in the details of construction andoperation as more fully hereinafter idescribed and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

Figure l is a perspective View of one form of the invention;

Figure 2 is a longitudinal sectional view taken on the line 22 of Figure1 and in the direction of the arrows;

Figure 3 is a transverse sectional view taken on the line 3-3 of Figure2 and in the direction of the arrows;

Figure 4 is an exploded perspective view of the block used to move theblade to which it is connected in and out of the housing together with adetent whose purpose is to lock the blade in the selected position;

Figure 5 is a top view of a suggested blade;

Figure 6 is a top view of another suggested blade having differentindicia thereon and provided with one less slot than Figure 5;

Figure 7 is a top view of further blade with other indicia on it and oneless slot, the blades of Figures 5, 6

and 7 being adapted to rest upon each other in nested fashion to formthe group of blades shown in Figure 2-,

Figure 8 is a top view of the locking means and means of extending theblades together with suggested indicia thereon to indicate the scalewhich is to be extended into view when a particular block is actuated;and

Figure 9 is a fragmentary top view of a modified locking device for oneof the blades.

As shown best in Figures 1-3, the multiscale drafting instrument or rule10 has a specially designed housing including an upper plate 12 and alower plate 14, each of which is arcuate in cross-section. Plates 12 and14 are thin and elongated, and are held spaced from each the housingwill come In this way, the

, from its central rest 2,8231% Patented Mar. 18, 1953 other by endwalls formed by spacer blocks 16 and 18. In this way, elongatedentrances 19 and 20 are formed along the edges of the instrument 10.

Two or more blades having scales thereon may be provided within thehousing. For illustrative purposes only, three blades 22, 23 and 24respectively are used in the make-up of instrument 10. They are adaptedto be nested with each other with the blade 22 on the bottom, the blade23 in the middle and theblade 24 on the top. Various indicia may beplaced on the edges of the blades in order to form scales of varioustypes. 7

In blade 22, there are a pair of slots 25 and 26. Similar slots 27 and28 are formed in blade 23, while other slots 29 and 30 are formed inblade 24. When the blades are nested, all of the slots on the left sidesof the blades are aligned (Figure 2) and all of the slots on the rightside of the blades are aligned. Guide block 32 which is secured to theplate 14, is fitted in slots 25, 27 and 29. An identical guide 34 alsosecured to plate 14 is disposed in aligned slots 26, 23 and 30. Guidemeans 32 and 34 function to prevent the blades from being separated fromthe housing, and function in a guiding way to make certain that theblades enter, pass through or are withdrawn through entrances 19 and 20smoothly and Without jammmg.

Means for extending a selective blade through a selected entrance 19 or20 are attached to the various blades. For the top blade 24, there is ablock 36 fixed to it at approximately its center, and this block mayhave it upper surface knurled, as at 38. Block 36 extends through a slot40 in plate 12. A detentj42 is carried by the block 36 and coacts withthe notches 44, 45 and 46 formed in an upstanding rib on plate 12adjacent one longitudinal edge of slot 41). Suitable markings may beplaced on the plate 12 adjacent slot 40 to indicate which scale will beextended when the block 36 is pushed from its retracted position withdetent 42 in notch 45 either to the notch 44 or toward the notch 46.

Block 48 is fixed to the top surface of blade 23 and it is adapted to beactuated to push the blade 23 through either of the entrances 19 or 20and to withdraw the blade into the housing. In order to be accessiblefrom the exterior of the housing, the block 48 is passed through anopening Si) in the blade 24 prior to being passed through the slot inthe plate 12 adjacent which a looking mechanism identical to thatdescribed in connection wtih block 36 is provided.

A block 52 which is fixed to the top surface of blade 22 and whichpasses through slots 53 and 5d of blades 23 and 24, respectively, isused for actuating the blade 22. Block 52 has a locking detent whichcoacts with locking notches along the side of a slide in top plate 12for the same purposes as described in connection with the blocks 48 and36 of blades 23 and 24.

As an alternative for the detents 4'2 and locking notches such as thoseat 44, 45 and te, a block 55} may be used (Figure 9), this block havinga generally pointed end 69 removably disposed in the series of Wells 61,62 and 63 formed in a spring bar 64. This spring bar is secured to anupstanding rib 65 on the top plate of the housing and extends slightlyover the slot within which the block 555 is operable. in use of eitherstructure, however, the user of the multiscale rule selects the scalethat he desires and then pushes the appropriate block position to oneend of the slot within which it is operable the other, depending onwhether he desires the scale to be extended through the entrance 19 orthe entrance in the housing. When extended, the locking means will holdthe scale in the extended position so that it will not move or wigglewith respect to the housing.

In use of the multiscale rule, it is simply placed on the drawingsurface. in this regard, the lower plate 14 has its longitudinal edges63 and 70 beveled to compensate for the curvature of plate 14 in havingplate 14 rest firmly flush upon the drawing surface. The longitudinaledges of each blade, for example, edges 72 and 74 of blade 22, aresimilarly beveled so that when the blade 22 is extended from thehousing, it also fits flush against the drawing surface. The curvatureof the housing and blades (Figure 3) together with this bevel makes itpossible to have the blades extended outwardly of the housing and fitfirmly against the plane drawing surface.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe inven tion to the exact construction and operation shown anddescribed, and accordingly, all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention asclaimed.

What is claimed as new is as follows:

1. A multiscale rule comprising a hollow elongated housing of arcuatecross-sectional form, said housing consisting of a pair of thin plateseach being arcuate in cross-section, arcuate spacers forming end wallsof the housing and secured to said plates holding said plates apart toform longitudinal entrances along two edges of said housing, a pluralityof elongated thin blades nested within said housing and being curved incrosssection, said blades having various scales thereon, means securedto said blades for pushing said blades through said entrances to bring aselected scale into view, said means comprising a finger grip membersecured to each blade, said housing having openings through which saidmembers pass, locking means for said blades connected with said membersand said housing, each blade provided with a slot extending transverselyof the blade, and a guide carried by said housing and located in theslots of said blades.

2. In a multiscale rule, a hollow which includes an upper and a lowerwall, means at the ends of said walls holding said walls spaced fromeach other to define longitudinal entrances along the edges of saidhousing, a plurality of elongated blades disposed in said housing andmovable through both of said entances selectively, said blades havingindicia thereon which is invisible when said blades are withdrawn intosaid housing and visible when projected through said entrances, saidwalls and said blades each being curved in cross-section so that saidblades and walls nest with each other, each blade having separate meansthereon for moving it through said entrances, locking devicesoperatively connected with each of said moving means to hold selectedblades extended through the entrance on either side of said housing andwithin said housing, and guide means operatively connected with saidblades and said housing to constrain the movement of said blades withrespect to said housing.

3. The multiscale rule of claim 2 wherein said locking means includes anupstanding rib on said upper wall, and yielding means operativelyconnected between said upstanding rib and said separate means in orderto hold said separate means and hence said blade to which it isconnected for retaining said separate means in selected positions.

elongated housing References Cited in the file of this patent UNITEDSTATES PATENTS 2,322,248 Miller June 22, 1943 2,634,504 Jennings Apr.14, 1953 2,672,692 Kucera Mar. 23, 1954 FOREIGN PATENTS 360,386 GermanyOct. 2, 1922 273,443 Great Britain July 7, 1927 126,509 Sweden Oct. 25,1949

